Welding of keys to can ends



J. G. HAYES WELDING OF KEYS TO CAN ENDS Aug. 17, 1948.

2 sheets-sheet 1 Filed Feb. 21, 1945 \Ig. 17, 1948. J, @HAYES v2,447,012

WELDING 0E KEYS To CAN ENDS Filed Feb. 21, 1945 '2 sheets-sheet 2 IN VEN TOR.

A T 70E/Vix? Patented Aug. 17, 1948 UNITED STATES PATENT OFFICE WELDING F KEYS TO CAN ENDS John G. Hayes, San Mateo, Calif., assignor to American Can Company, New York, N. Y., a corporation of New Jersey Application February 21, 1945, Serial No. 579,021

5 claims. l

This invention relates to an apparatus for electrically welding opening keys on sanitary can ends and has particular reference to holding the key in welding position on the exterior surface lof a can end which carries a protective coating on the inner surface, which coating may have electric current insulating or non-conducting properties, so that one electrode engages against that uncoated non-insulating portion of the coated surface of the can end which constitutes the gasket lining groove of the end.

In the can making art it is often desirable to have a protective coating on the inner surface of the can end and it has been found that the most effective coating requires a high baking temperature. The can manufacturer therefore has applied the protective coating on the fiat sheet or blank prior to the can body Ior the can end being formed from such sheet or blank. The gasket material for the end joints between the can end and the can body will be applied later and accordingly the outer flange portion of the area of the can end is left uncoated since this is the part that will subsequently include the lining groove of the end, this area being in contact With they M lining material.

The present invention contemplates an apparatus designed for Welding by engagement of one of the electrodes in the uncoated lining groove of the end, the opposite electrode engaging the key Which4 is positioned on the opposite surface of the end.

An object of the invention is the provision of an apparatus for Welding keys to can ends having a portion of the surface constituting the interior' surface coated with a protective coating and having a surrounding uncoated lining groove in the flange portion of the end, which uncoated portion is utilized for engagement with one of the electrodes during welding While the other` electrode engages the key and holds it in close metal to metal contact with the opposite surface of the can end.

A further object of the invention is the provision of a Welding apparatus of the character described wherein a can cover and a key are brought into position between two electrodes at a welding station, one electrode engaging the flanged uncoated portion of the can end and the opposite electrode engaging the key.

Still another object is the provision of a can end and opening key holding device located at a Welding station wherein the annular lining groove formed in the flange portion of the can end receives an annular electrode, the can end being 2 held down at the flange to obtain a better welding AContact at this place While the key is similarly held in close metal to metal contact with the can end at another place, neither electrode or other apparatus part causing burning or other defacement of the coated surface.

Yet another object is the provision of a welding apparatus of the character described which functions to support the .coated portion of one surface of a can end by means of an insulating member to the end that the key and can end are more positively held in close metal to metal contact for the welding apparatus Without marring the surface coating of the end.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure l is a perspective View of an inverted can end having a portion of its inner surface coated with a`protective coating, such an end being adapted for welding thereto of an opening key by means of the apparatus of the present invention.

Fig. 2 is a plan view of the principal parts of a welding apparatus embodying the present invention;

Fig. 3 is a longitudinal vertical sectional view of the apparatus as taken substantially along the line 3-3 in Fig. 2, parts being shown in front elevation;

Fig. 4 is an enlarged vertical sectional detail 0f the welding head illustrating a can end and an opening key in position for Welding;

Fig. 5 is an enlarged view in vertical section taken substantially along the line 5-5 in Fig. 2; and

Fig. 6 is a perspective view of the can end with its Welded key, this view showing the outer eX- posed opposite surface of the end as compared with Fig. 1 and indicating the effect of a subsequent lining step which has applied a lining cornpound in the can end groove.

In the present invention the welding apparatus is of such a nature as to adapt it for the welding of metal opening keys a (Fig. 6) having the usual welding projections b, to paneled metal can ends c in Which the interior surface of the can end is centrally coated with a protective coating d. This coating extends over the surface which will be exposed on the interior of the can after the end has been double seamed to the can body in the usual manner but the surrounding outer ange portion of the end indicated by the letter e is left uncoated. This ange portion of the end embodies a usual gasket lining groove f which is formed to receive the usual compound lining gasket g.

It is desirable'inautomatically welding keys to can ends that provision be made for centering the key in its desired location in the can end. Accordingly there is illustrated a key receiving depression l1, (Figs. 1, and 6) in the centerof the outer depressed paneled surface. The key after being rst assembled-Withlthe canend will be retained in correct position in this depression for conveyance to the welding station.

The principal parts of a suitable welding apparatus are best shown in Figs. 2 to 4, inclusive, and comprise in general a frame Il formed with a flat top port-ion I2 on which is mounted a discplate-l3 constitutingasupport for. a canend c. The frame M is formedv with a depending boss l5A which provides a bearing for a vertical shaft I6 which carries a shouldered sleeve I1, on which isfmounted a turret i8. The shouldered sleeve l1 is adapted to rotate within the boss l5 and with the shaft Hi to which it is keyed.. The turret 'I-B i-s fastened onto the top of the sleeve, the disc plate |3-beingformed with a clearance opening I9 to allow such attachment.

The turret I8 receivesa can end c ata cover feed stationA (Fig. 2) and anropening key a at a key feeding station B. The turret positions the assembled end and keyV at a welding station C for the welding operation. lFor this purposethe turret is formed with a plurality of circular openings 25 arranged concentric to the axis of the turret shaft I6. These openings 25 are slightly larger `than the diameter. of a can end b and at the cover feeding station A the can end is dropped into an opening from above, in any suitable man- `vner.

In'cominginto position within the opening 25 at the station A, the can end falls upon two spaced concentric shoulders or circular tracks 26, 2-1 cut in the upper surface of the disc platev I3. A depression groove 28 having the bottom of the groove lower than the upper surfaces of the tracks is cut inthe disc plate between -thetracks to clear the countersunk panelled center of the can end. This is best Vindicated-in dotted Alines -in-Fig. 2 and-in-full lines in Figs. 3 and 5.V Oneend of the groove 28A at station A takes the form of a circular'end wall 29 having its center aligned Awitlithe center of the opening. 25 of the turret at that station.

The circular concentric tracks 26, 21 guide `/thecan end through'stations A and B, and idle station D; to the welding station: C. After welding the tracks continue to another idle station E and lthence to va vdischarge station F.

Thev turret IIB is intermittently lrotated so that each. of its-openings `25 is brought to rest at each of the stations A, B, D, C` and lil.v Accordingly a can end c having been fed into the turret at the station A, is next .advanced to station B by the intermittent rotation of the turret. To effect such -advancement of thel end, la feed block 3l (Figs. 2 and 5) is secured to the under surface of the, turret i8 just back of the edge of an openvthe can end moving along and being supported by the shouldered tracks 26, 21.

At station B the opening key a is fed from above onto the can end in any suitable manner so that the welding project-ions b are at the bottom, that is, these projections come into contact with the upper panelled surface of the can end. In such a feeding action the key drops inside of the depressionJt which depressionas already suggested retains the key in proper centralized position relative to the can end until the key is welded into its more permanent position on the end.

At the next step rotation of the turret the can end with its pocketed key is advanced to station D and is brought to rest. This is an idle station and no work is accomplished. It will be understood that during the advancement and rest of the can end at stations A, B and D, its coated portion d is free Iof the bottom of the groove 28, the curled edge of the end resting on the tracks and 21. In this way scratching of the coated surface is prevented.v

At thenext step rotation of the turret, the can end with its key is brought to rest at the welding `station C. At this station the disc plate I3, in which the tracks 26, 21 are out, is bored out to receive an insulated stepped ring 35 (Figs. 2 and ll) which extends entirely through the disc plate. The upper surface of this ring is flush with the upper surface of the disc plate and the ring'is cut with circular slots leaving shoulders 36 and 31 to form a continuous adjoiningtrack section for the curled edge of the can. endv while at the station C. This curved track section has vthe upper surfaces of the shoulders 36, 31 flush, respectively, with the tracks 26, 21 andy thereis also a clearance groove 38 corresponding to the depression 28 in the disc plate.

In the centered position of the .can end (Fig. 4) at station. C, the end is directly over but spaced above a lower elec-trode 4|.. Electrode 4l is annular in shape and is concentric with the insulating ring 35. It is narrower than the Width of the lining groove f of the can end. The electrode 4I may be built up as shown, being of cuplike construction, the .annular electrode proper merging at the bottom into a circular base 42. This electrode unit is mounted upon the upper endl of a shaft 43 which is vertically movable within a boss 44 formed in a bracket 45 (see also Fig. 3) constituting a part ofthe frame l.|.

The shaft 43v .extends below theboss 44 and is reduced in diameter as a lower stem 46. The sternA carries a grooved collar 41 which is held on the stem by a lock nut v48, threaded into the end of the shaft. A spring 49 is located on the stem between the collar 41 and the enlarged section of the shaft. This provides a yielding connection for theshaft and allows for raising of the lower electrode 4I under a spring compression.

The lower electrode 4I is raised and lowered by cam action and for this purpose a lever 5l is pivotally mounted on a fixed horizontal pin 52. One arm of the lever is formed with a yoke section 53 which is of a shapeto straddle the grooved section of the ycollar 41. The4 ends of the yoke have rounded surfaces on opposite sides of the collar where it engages in the groove. The pivot pin 52kmay be held in lugs 54 projected down from the frame bracket .4.5.

'The opposite arm of the 'lever 5i extends outwardly and radially `and carries a cam roller 55. This roller is adapted to operate in a cam groove 56 formed in aV face cam 51 which is mounted on and rotateswith a horizontal shaft'58. Shaft 58 is journaled in bearings .59,formed in bra-ckets `which may be boltedto the frame l I. VThe shaft 58'is continously rotated in any suitable manner.

Centrally of the lower electrode 4| is an insulating disc or plate 62. This may be held centrally of the electrode base 42 by bolts 63 which preferably extend not only through the electrode base but also hold the electrode in position by threadedly engaging the upper end of the shaft 43.

An insulated hold-down ring 'II (Fig. 4) is located at the station C and is held on a disc-like base I2 of an upper electrode member 13. At the time the can end comes to rest in station C preparatory to welding. the hold-down ring 1| is in a raised position. The bottom of the ring is relieved along its outer corner periphery as at 'I the unrelieved part extending down as a depending lower annulus 'I5 which is slightly smaller than the counter-sink panelled diameter of the can end.

The upper electrode member 'I3 includes an integral depending portion l. The lower face of the said electrode portion is substantially flush with the lower face of the hold-down ring II. This electrode is spaced above and in alignment with the end portion of the key a when cover and key are brought into the welding station. The holddown ring base 'I2 is secured to the lower end of a vertically movable shaft I'I by screws '18. This shaft is preferably disposed in axial alignment with the lower electrode shaft 43.

The shaft 'Il (see also Fig. 3) is adapted to move up and down within a boss 8| formed on an upper bracket 82 (see also Fig. 2) which is mounted upon and secured to the frame I I. Shaft 'Il preferably is splined at 83 to prevent turning within the boss 8| and it extends above the boss. This shaft is formed with a reduced. diameter, upper stem 84 which passes through a grooved collar 35, the latter being retained upon the shaft by a lock bolt 86 threaded into the upper end of the shaft. A compression spring 81 is located on the stem 46 and is .confined between the lower edge of the grooved collar 85 and the shouldered part of the shaft TI. This provides a yielding connection for the shaft and allows for lowering of the upper electrode 'l5 an-d the hold-down ring 35 under a spring compression.

The shaft ll, the electrode "I and the holddown ring TI are moved upand down by cam action. 'For this purpose there is provided a lever 9| (Figs. 2 and 3) which is mounted on a pivot pin 92 carried in bearings 93 formed in the bracket S2. An inner arm Se of the lever 9| is formed with a yoke 95 which operates in the groove of the collar 85. The ends of this yoke straddle the collar 85 and are rounded to engage the groove walls of the collar.

An outer arm 91 of lever QI extends down and projects outwardly in an end which carries a cam roller 98. This roller operates in a cam groove 99 formed in a face cam IUI secured to and rotatable by the shaft 58.

With the can end c and its opening key a at rest at station C and between the upper and lower electrodes, the cams 5l, IUI operate their respective levers 5I, 9| to raise the lower electrode 4I and parts carried thereby and to lower the upper electrodes 16, the hold-down ring 1I and parts carried thereby. This position is shown in Fig. 4.

In attaining such a position, the insulating disc 62 moves up against the coated surface d of the can end c and the annular lower electrode 4I passes into the lining groove f where it engages against the uncoated ange part e of the can end. At the same time the hold-down ring 'II moves down and backs up the flange'of the can end. The annulus 'I5 of the hold-down ring centers the can end and then holds it in correct welding position. The upper electrode 'I6 presses down against the end of the key a and the welding projections b are pressed into tight metal engagement with the upper surface of the can end as it is supported on the insulating disc $2. This is the Welding position.

With the parts thus in proper position, a suitable welding current is passed between the upper electrode 'I6 and the lower electrode #il by'way of the opening key a and through its welding projections b, and by way of the can end wall and its flange e where it engages the lower electrode. In addition Fig. 4 discloses a wiring diagram which indicates a source of electric energy for the welding operation. This is shown in the form of a welding transformer |05 having a primary circuit |06 and a secondary circuit Iil'l.

The secondary circuit includes a wire ISS leading from the transformer |55 through the shaft I1 and electrode member 'I3 to the upper electrode portion 'I6 and a wire |09 leading from the transformer to the lower electrode il by way of the shaft 43.

After the opening key a has been welded to the lcan end c the end and key are advanced by the turret I8 to the idle station E (Fig. 2). At this station no work is accomplished and following the rest period the end with its attached key is moved next to the discharge station F. The discharge of the can end at station F takes place prior to the pocket 25 of the turret, in which the can end is located, coming to rest at the next adjacent station, this being at an idle or blank station G.

Just beyond the idle station E and at the approaches of the discharge station F the shouldered track 26 formed in the disc plate I3 terminates and a lateral discharge track II I formed in the disc plate forms a continuation of the track. Opposite this the track 27 also terminates and joins into a continuing lateral track I I2, also formed in the disc plate.

The groove 28 also terminates the discharge station F, since it is here that the can end leaves the turret i3. An arcuate clearance groove I3 is cut in the disc plate I3 between stations F and A and this provides clearance for the block 3| during its passage through idle station G. The groove I i3 is not as deep or as wide as the groove 28 and accordingly a shoulder IM is formed at the discharge station F where the groove |I3 joins with the groove 28. This shoulder assists ,in stripping the can end with its key from its position below the opening 25 of the turret, the block 3| camming the end outwardly and causing the curled edge of the end to pass onto the discharge tracks I I I, I I2.

A discharge chute i I5 which may be an integral part of the frame I I, extends outwardly from the discharge station F. This discharge chute is formed with groove tracks II, Il'i which form continuations of the tracks Ill, H2. The disc plate as well as the discharge chute are also grooved at I I8 for clearance of the panelled center of the end. By means of this construction the can end with its attached key is swept from the turret II and from the disc plate I3 discharging from the machine by way of the discharge chute II5.

The discharge chute may lead into a gasket liner or other suitable machine wherein the gasket g is deposited in its lining groove f. This lining step, however, forms no-part of the-present inven-A tion.

It is thought that theinvention and manyof its.v attendant advantages will be understood fromr the foregoing description, and it `Will-be apparent that various changes may be made in the form,`

tion only of Aone side thereof, the combination ofan` electrode for engaging the uncoated portion of the partially coated canend surface, a second electrode for pressing an opening .key against the opposite surface of the can end to force the vkey welding( projection into close metal to metallcontactlwith the can end, spaced electrically insulated means on opposite vsides of the can end respectively disposed oppositely to said electrodes for clamping the can end therebetween during a Welding operation, and electrical means for passing a welding current between said electrodes throughl the key and can end to` fuse them together in a permanent Welded bond.

2. In an' apparatus for welding metallic openingkeys havingwelding projections thereon to sheet metal can ends having a protective coating covering a portion of the surface on one side thereof, the combination of lan electrode for engaging the uncoated portion of the coated can end surface, a second electrode for pressing' an openingk'ey against the opposite surface of the can end to force the key welding projections into close metal to metal contact with the can end, said electrodes being spaced from one another in the plane of the can vend surface for thedescribed purposes, spaced electrically insulated means on opposite sides of the can end respectively disposed oppositely to saidv electrodes for clamping the can end therebetweenv during a welding operation, and electrical means vfor passing a Welding current between said velectrodes through the key and can end to fuse them together in a permanent welded bond. y

3.- In an apparatus for welding metallic opening keys having Welding projections thereon to sheet'rnetal can ends having a protective coating coverln'g'a central portion of the surface on one side thereof and also having an uncoated anged peripheral portion, the combination of a movable electrode for engaging the uncoated flanged portion of the can end'surface, a second movable electrodeV forA holding an opening key against the opposite surface of the can end to force the key Welding projections into close metal to metal contact with the can end, said electrodes being spaced radially from one another in the plane of the can end surface, electrically insulated means for holding the uncoated flanged edge portion of said can end'against said rst mentioned electrode,

a second electrically insulated means. spaced ina` wardly from said first mentioned-insulated means for holding the can endiengaged opening .key` against said second electrode, and electricalmeans for passing a Weldingcurrent between said electrodes and through the key and canend to fuse them together in a permanentwelded bond.

4.r In an apparatus for welding metallic open. ing keys having Welding projections vthereon to sheet vmetal can ends-having av protective coating covering acentral portion Aof the surface on Ione side thereof and also having an uncoated flanged edge portion, the combinationof a turret for con-4 veying and for centering la cany end into a Weld` ing station, a movable electrode forengagingthe uncoated flanged portionof acan endat said station, a support plate for holding .thecan vend While at said. station, a hold-down memberforretaining the can end against said electrode and against said plate, .a secondmovableelectrode for pressing. againstan opening key, positioned on the can end to force the welding projectionsof the key into close metal to metal contact with the can end, and electrical means for passing aweld.-y ing current between said electrodes` and through the key and can end to fuse them together in a permanent welded bond.

5. In an apparatus for welding metallicopen.-` ing lkeys having Welding .projections thereon .to sheet metal can ends having a protective coating covering a central portion of thesurface on one side thereof and also having an uncoated flanged edge portion on said side, the combination of feedingv means for conveying and Afor centering. a can end into a Welding station,ia movable' annular electrode for engaging the uncoated flanged por,- tion of a can end at said station, a movablecen, trally disposed insulatingplate forengaging and holding the coated portion of the .can end at said station, av movable insulating ring for retaining the can end' on said plate and on said electrode when the parts are in engagement'with a can end, an opposed centrally disposed. electrode mov.

REFERENCE S CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date'.

1,296,780 Dyer Mar. 11,1 .1919 1,635,536 Butter 1 July 12, 192.7 1,699,091 Butter Jan. 15; 1929 1,863,850 Halloway June 21, 1932 2,326,805 Shmurak Aug. 1'7, 1943 2,338,002 Mero 1 Dec.. 28,; 1943 

